Measurement of Organochlorines in Commercial Over-the-Counter Fish Oil Preparations: Implications for Dietary and Therapeutic Recommendations for Omega-3 Fatty Acids and a Review of the Literature

Archives of Pathology & Laboratory Medicine, Jan 2005 by Melanson, Stacy Foran, Lewandrowski, Elizabeth Lee, Flood, James G, Lewandrowski, Kent B

The sparse evidence on the levels of PCBs, PBBs, and OC pesticides in fish oil and the current media hype over toxins in fish prompted our study on the content of PCBs, PBBs, and OC pesticides in fish oil. Our study illustrated that none of the 5 over-the-counter brands of fish oil contained detectable levels of PCBs or other OCs. We also found negligible levels of mercury in fish oil in our previous study. The lower limits of detection for PCBs, PBBs, and other OCs in this study were 400 ppb, 400 ppb, and 200 ppb, respectively. This method is less sensitive than some other methods, which can detect as low as 50 parts per trillion. However, our data and limits are sufficient to show that (1) fish oil contains at least 5 times less PCB and 25 times less DDT than the FDA daily recommended limits, and (2) fish oil contains less OC than fish high in the food chain. For example, regular consumption of fish from the Great Lakes (400 g of fish per week, with PCB levels of 0.753 �g/g, would amount to 301 �g of PCBs per week) would expose humans to at least 70 times more PCBs than routine doses of fish oil (1.5 g/d, that is, 10.5 g/wk, with PCB levels of 0.4 �g/g, would amount to 4.2 �gg of PCBs per week). A similar calculation illustrates that fish from the Great Lakes have 120 times more OC pesticides than fish oil supplements.

Fish oils provide the advantages of omega-3 fatty acids with minimal toxic risks. Our data suggest that even large amounts of fish oil can be consumed without risk of toxicity. This is particularly important because high doses of fish oil supplements are currently being used to treat hypertriglyceridemia and to augment antidepressive therapy in patients with bipolar disorder and unipolar depression.10,11,13 Our data concerning the levels of OCs suggest that fish oil supplements may be preferable to fish consumption as a dietary guideline for the general population and as a therapeutic source of omega-3 fatty acids in patients with cardiovascular disease and depression.

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